#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define rep(i, a, b) for (int i = (a); i <= (b); i++)
#define per(i, a, b) for (int i = (a); i >= (b); i--)
#define endl '\n'
const int N = 2e5 + 5;

int n, m;
int a[N];
int sum[N];
int f[N], g[N];
void solve() {
  cin >> n;
  rep(i, 1, n) cin >> a[i];
  rep(i, 1, n) sum[i] = sum[i - 1] + a[i];
  rep(i, 1, n) f[i] = max(f[i - 1] + a[i], -sum[i]);
  per(i, n, 1) g[i] = max(g[i + 1] + a[i], -(sum[n] - sum[i - 1]));
  int ans = f[n];
  rep(i, 1, n) ans = max(ans, f[i - 1] + a[i] + g[i + 1]);
  cout << ans << endl;
  return;
}
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  int t;
  t = 1;
  while (t--) solve();
  return 0;
}